The ministry’s warning followed calls by supporters of former Egyptian president Mohamed Morsi, who was ousted by military last July, for demonstrations on the 1973 Arab-Israeli war anniversary.

"The Egypt Anti-Coup Alliance repeats its call to all Egyptians to continue their protests in every part of Egypt, and to gather in Tahrir Square on Sunday, October 6, to celebrate the army of that victory and its leaders," the Anti-Coup Alliance of Islamist bloc said, Agence France Presse (AFP) reported.

Earlier attempts on Friday by protesters against the army's July 3 overthrow of Morsi to reach Tahrir Square sparked clashes with security forces who responded with tear gas and warning shots.

Four people were killed in Cairo's deadliest protest violence in more than a month as demonstrators clashed with security personnel and supporting thugs.

Political tensions have gripped Egypt and hammered the economy since the army ousted Morsi in July, installed an interim government and presented a political roadmap it promised would bring fair elections.

Authorities have cracked down hard on the Brotherhood, which won every election since Mubarak's fall.

The Brotherhood accuses the military of staging a coup and sabotaging Egypt's democracy by removing Morsi, the country's first freely-elected president.

Risky Attempts

Analysts said the Islamists' call for rival commemorations of the 1973 war marked a high-risk attempt to strip the current high command of the conflict's legacy of patriotic pride in the army.

"They will try to show that the present army is not the army of all Egyptians, but only of those who backed the coup," Hassan Nafaa, professor of political science at Cairo University, told AFP.

"But this message will not go down well," the professor, who supports the military move, added.

"Egyptian people are not against the army as they were against the police in January 2011. If there is violence tomorrow, the Muslim Brotherhood will be the loser".

Both the United Nations and the United States also voiced alarm at the violence and made fresh pleas for peaceful protests.

The protesters "have a responsibility to protest peacefully, to not incite violence, to not undertake violence of their own," said deputy US State Department spokeswoman Marie Harf.

In New York, UN chief Ban Ki-moon stressed "the importance of peaceful protest, respect for freedom of assembly and commitment to non-violence," his spokesman Martin Nesirky said.